Microglial cells elaborate trophic factors and cytokines and remove toxins and debris from the extracellular space in the central nervous system, acting analogously to peripheral macrophages. Over the past two decades, increased attention has been directed at the role of microglia, not only in normal physiology, but also in mediating neurotoxicity. Activation of microglia is inherent to multiple neurodegenerative disorders and exposure to toxic compounds. In large measure, these revelations have come about as a result of technologies that enable researchers to obtain high yield and purity primary cultures of rodent microglia. The mechanical isolation protocol discussed in this unit offers an economical method to isolate large amounts of microglia in a short and not too labor-intensive manner. Most importantly, it ensures a high yield of cells with great reproducibility. Given the ever-increasing importance of microglia to the field of neurotoxicology research, the ability to isolate large quantities of primary microglia makes it possible to investigate the role and mechanisms associated with microglial modulation of neurotoxicity. We provide a detailed description on the methods that are routinely used in our laboratory for the isolation and culture of microglia, with emphasis on the steps that are deemed most critical for obtaining pure and healthy cultures.